Jesus must have known his followers would have a hard time believing Mark 10:29, so he said first, "I tell you the truth." Then he makes a big promise: anyone who loses homes, family or fields for His sake "will receive 100 times as much in this present age of homes, brothers, sisters, mothers, children and fields."
Now, that is a remarkable statement. Jesus rarely promised his followers tangible, earthly goods and possessions. But here he seems to be promising to cover our losses a hundred times over.
What does He mean?
Author James Lee Burke, creator of the detective Dave Robicheaux series of crime novels, once called the Roman Catholic Church "the largest social club in the world." He meant it in a good way: drop a Roman Catholic in almost any town in the western world and chances are he can find a church community and school for his children. If he chooses, he can be surrounded by people of faith and good will who will support him in his need.
I suspect this is generally true of all Christian churches. Lest we take it for granted, imagine a world where the ONLY people who would lift a finger to help you were those of your own family. If you were separated from them by geography or ostracism, you would be truly alone in the world. To make matters worse, both your employment and "retirement" would depend solely on your family's means and good will. No one else would feel obliged in the slightest to help you.
Then along comes Jesus. His teaching, blood and resurrection power creates a Kingdom where people serve each other. And not just Christian serving Christian, but serving non-Christian as well. Every man in need would have a neighbor. As this gospel took hold, the early Romans were amazed at the Christians who cared for sick and dying strangers - an unheard-of practice. Today, people in Haiti with no "field and homes" of their own due to the earthquake etc. are blessed by hundreds of church groups showering them with the bounty of their own fields and homes. And Haiti is just one example of thousands. On the shelf behind me as I write these words is a stack of letters of condolence. I can barely hold them all in one hand. Each one is from one of those hundred-fold fathers, mothers, brothers and sisters.
The system is not perfect. But it is safe to say that 20 centuries later, the rich, commonplace tradition of Christian brotherhood and support is a promise fulfilled.